Certainly, having Democrats control Congress by a huge majority is an advantage for any President. But it may also pose a political danger to a President, especially for one who, like Obama, came to power thanks to his party's left wing.

Having to deal with a Republican Congress allowed Bill Clinton to stick safely to the middle. And Republicans excused Ronald Reagan for failing to enact some of the policies dearest to them because they understood that the huge Democrat majority in the House made it impossible.

In contrast, now Obama has no excuse for failing to act on the left's agenda -- especially the parts he made pledges on, things like the Freedom of Choice Act. With his Congressional majorities, he's presumably got the votes.

If he fails to do those things (as he's now backtracking on is promise to abolish military tribunals for terrorists), he's going to break the hearts of his most steadfast supporters on the left and reveal himself to be "just another politician" -- an ugly outcome for someone whose radiant nobility is supposed to transcend politics entirely. If he acts on some of his more extreme promises, however, he risks alienating normal Americans.

The President is a very smooth talker, and he may be able to walk this tightrope. But it will be interesting to see.